Actually, I tend to disagree with MagSeal about operators that blacklist pilots.
Years ago I worked for one operator in Alaska that has been in operation for over 40 years and had developed an extensive "black list" and had every right to do so. Not one single pilot on that list was there for a bogus reason. And I qualify this with the following examples:
Pilot 1 claimed his mother was mortally ill and he had to go visit her immediately. The company paid to get a relief pilot out into the field to keep the contract customer happy, paid his airline ticket to go "see" his mother, gave him one week off with pay and promissed his job would be held open for him come hell or high water. Turns out he was full of hot air, as a week into this another company's Chief Pilot called me to verify employment. He lied to us and we paid blindly.
Pilot 2 was flying tours in an AS350B2 and had a reputation of hot-dogging. One day, as he came bailing over a cliff the intermittent high-rpm horn went off, but he thought the engine had quit and autorotated onto a river bank. Another helicopter had to be dispatched to pick up his passengers. Turns out he was telling all his passengers after landing how he had saved their lives from certain doom.
Pilot 3 was asigned to move drills in very challenging topography. He had over 16,000 hours experience. The customer kept calling praising how they never had such a great pilot who would fly in any weather condition - as a matter of fact, they mentioned multiple times how good he was flying in fog because the first thing they would see was a load of drill rods on a 150' line prior to seeing the helicopter. He always got his crews out into the hover-holes, even if it ment flying tree top to tree top. No matter how heavy the loads, he would get them off. Well, two months later, after sending the engine out for scheduled maintenance, we got notified that the engine was completely trashed. Had to replace it with a new one. Lost a lot of money on that contract.
I could go on and waste webspace giving more examples of "black listed pilots." There definitely is a valid reason for having such a list as long as a standard is developed defining what actions are required to be placed on the black list. Needless to say, that list is unofficially shared with other operators. This practice might not be legal, but it sure has saved many companies from hiring weak, unsafe, dangerous pilots.
However, getting back to the original thread, burning bridges can sometimes be a necessity and other times it can hurt you. It all depends on the situation and company.